If they are halogen headlight and you changed it to be HID headlight. You may void your headlight warranty. Because you may need to drill a hole on the light bulb cover for the wire that connected to HID bulbs and ballast. You can change your yellow light bulbs to some 7500K or 8000K halogen light bulbs to make it white color. Or replace your whole headlight to be a HID projector headlight.

However, avoid the common mistake of buying a bulb that is not rated correctly for your car. Your brighter lights run the risk of melting the wiring harnesses, which is not covered under warranty because you broke the car by replacing a part with something that was not rated correctly. It's the same difference as putting a 100watt bulb in a lamp rated for a 20w. When it melts, you can't blame the lamp maker. I know at least half a dozen people who've done this (this impacts halogen bulbs, not HID's which are a different beast)